Aqueous surfactant compositions

ABSTRACT

What are proposed are aqueous surfactant compositions comprising one or more of each of alpha-sulfo fatty acid disalts, sulfo ketones, alkyl (ether) sulfates, soaps, inorganic salts of sulfuric acid and water, where the structures of the compounds mentioned and boundary conditions that are to be observed can be found in the patent claims. These compositions have good foaming ability and pleasant sensory properties of the foam and good skin compatibility and they are suitable for cosmetic agents as well as detergents and cleaner.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is the U.S. national phase of International Application No.PCT/EP2017/061275, filed May 11, 2017, which claims the benefit ofEuropean Patent Application No. 16171977.8, filed May 30, 2016.

FIELD OF THE INVENTION

The present invention relates to aqueous surfactant compositions with acontent of alpha-sulfo fatty acid disalts, sulfo ketones, soaps,inorganic salts of sulfuric acid and specific sulfates that are selectedfrom alkyl sulfates and alkyl ether sulfates.

PRIOR ART

Anionic surfactants are some of the most widespread interface-activecompounds and, apart from being used in detergents and cleaners, arealso used for diverse purposes in the field of cosmetics. Customaryanionic surfactants as are used in particular in cosmetics are the saltsof alkyl ether sulfates (alkyl polyether sulfates, fatty alcoholpolyglycol ether sulfates, in short also ether sulfates). They arecharacterized by a strong foaming ability, high cleaning power, lowsensitivity to hardness and grease and are used widely for producingcosmetic products such as, for example, hair shampoos, foam or showerbaths, but also in hand dishwashing detergents.

For many current applications, apart from a good interface-activeeffect, further requirements are placed on anionic surfactants. A highdermatological compatibility is required in particular in cosmetics. Inaddition, good foaming ability and a pleasant sensory property of thefoam is generally desired. Furthermore, there is a need for anionicsurfactants which can be produced at least partially from biogenicsources and specifically also renewable raw materials.

WO-A-92/15660 discloses liquid cleaners with a content of sulfo-oleicacid disalts. It is disclosed that sulfo-oleic acid disalts are able toreduce the viscosity of surfactants or surfactant mixtures for cleanersparticularly those based on fatty alkyl sulfates, fatty alkyl ethersulfates, alkylpolyglucosides and fatty acid monoethanolamides andindeed just as effectively or even better than by adding ethanol orhydrotropes (page 2, second paragraph).

DE-A-37,07,035 discloses shaped cleaning products comprising fattyalcohols, palmitic acid and/or stearic acid, which may optionally be insoap form, and alpha-disalts. According to the information at page 2lines 57 ff., the subject-matter of the application of DE-A-37,07,035 isbased on the observation that the shapability and smoothness of shapedcleaning products based on sodium alkyl sulfate that contain fattyalcohols and fatty acids as plasticizers and binders can be noticeablyimproved by the addition of relatively small amounts of an alpha-sulfofatty acid salt (“alpha-disalt”).

DESCRIPTION OF THE INVENTION

The object of the present invention was to provide aqueous surfactantcompositions which are characterized by the properties specified below:

-   -   good foaming ability.    -   pleasant sensory property of the foam.    -   good skin compatibility.

The invention firstly provides aqueous surfactant compositionscomprising

-   -   one or more alpha-sulfo fatty acid disalts (A) of general        formula (I),        R¹CH(SO₃M¹)COOM²  (I)    -   in which the radical R¹ is a linear or branched alkyl or alkenyl        radical with 6 to 18 carbon atoms and the radicals M¹ and        M²—independently of one another—are selected from the group        comprising H, Li, Na, K, Ca/2, Mg/2, ammonium and alkanolamines,    -   one or more sulfo ketones (B) selected from the compounds (F)        and the compounds (G),    -   where the compounds (F) have the general formula (VI)        R⁶CH₂—CO—CHR⁷(SO₃M⁸)  (VI)    -   wherein the radicals R⁶ and R⁷—independently of each other—are a        linear or branched alkyl radical having 6 to 18 carbon atoms and        the radical M⁸ is selected from the group comprising H, Li, Na,        K, Ca/2, Mg/2, ammonium and alkanolamines,    -   and where the compounds (G) have the general formula (VII)        (SO₃M⁹)R⁸CH—CO—CHR⁹(SO₃M¹⁰)  (VII),    -   wherein the radicals R⁸ and R⁹—independently of each other—are a        linear or branched alkyl radical having 6 to 18 carbon atoms and        the radicals M⁹ and M¹⁰—independently of each other—are selected        from the group comprising H, Li, Na, K, Ca/2, Mg/2, ammonium and        alkanolamines,    -   one or more sulfates (X) which are selected from the group of        the alkyl sulfates of the general formula (IIa) and the alkyl        ether sulfates of the general formula (IIb)        R⁷⁰SO₃M⁷⁰  (IIa)        R⁷¹O(CH₂CH₂O)₂SO₃M⁷⁰  (IIb)    -   where the radicals R⁷⁰ and R⁷¹ are independently a linear or        branched alkyl radical having 8 to 20 carbon atoms and the index        n is a number in the range from 1 to 20 and the radical M⁷⁰ is        selected from the group comprising H, Li, Na, K, Ca/2, Mg/2,        ammonium and alkanolamines,    -   one or more compounds (C) of general formula (III)        R⁴COOM⁵  (III)    -   in which the radical R⁴ is a linear or branched alkyl or alkenyl        radical having 7 to 19 carbon atoms and the radical M⁵ is        selected from the group comprising H, Li, Na, K, Ca/2, Mg/2,        ammonium and alkanolamine. Particularly preferred alkanolamines        here are monoethanolamine, diethanolamine, triethanolamine and        monoisopropanolamine.    -   one or more inorganic salts of sulfuric acid (D) of general        formula (IV)        (M⁶)₂SO₄  (IV)    -   wherein M⁶ is selected from the group comprising Li, Na, K,        Ca/2, Mg/2, ammonium and alkanolamine. In this connection,        particularly preferred alkanolamines are monoethanolamine,        diethanolamine, triethanolamine and monoisopropanolamine,    -   water,

where the following proviso applies:

-   -   If the aqueous surfactant compositions comprises one or more        ester sulfonates (E) of general formula (V),        R²CH(SO₃M⁷)COOR³  (V)    -   in which the radical R² is a linear or branched alkyl or alkenyl        radical having 6 to 18 carbon atoms and the radical R³ is a        linear or branched alkyl or alkenyl radical having 1 to 20        carbon atoms, where the radical R³ can logically be an alkenyl        radical or be branched only above 3 carbon atoms, and the        radical M⁷ is selected from the group comprising Li, Na, K,        Ca/2, Mg/2, ammonium and alkanolamines, it is the case that the        compounds (A) based on the totality of the compounds (A) and        (E)—must be present to an extent of 50% by weight or more—and in        particular to an extent of 90% by weight or more.

The aqueous surfactant compositions according to the invention arecharacterized by the following advantageous properties:

-   -   Good foaming ability and pleasant sensory property of the foam.        In this regard, it may be noted that particularly in the field        of cosmetics, foaming ability can be understood to mean        different aspects, for example it being possible to use both        foam volume, foam stability, foam elasticity, water content of        the foam as well as optical features of the foam such as, for        example, the pore size, for the purposes of assessing the foam.        The compositions according to the invention have a large foam        volume during the initial foaming. In practice, the initial        foaming takes place within a relatively short period (from a few        seconds to one minute). Typically, during initial foaming, a        shower gel or a shampoo is spread and caused to foam by rubbing        between hands, skin and/or hair. In the laboratory, the foaming        behavior of an aqueous surfactant solution can be assessed e.g.        by agitating the solution within a comparatively short time        period by means of stirring, shaking, pumping, bubbling through        a gas stream or in another way. Subjective assessment of the        foam sensory property can be made by test subjects. For this        purpose, aspects such as creaminess, elasticity, moldability of        the foam may be assessed.    -   Good skin and mucosa compatibility. These can be detected by in        vitro methods known to those skilled in the art (e.g. RBC or        HET-CAM) and also by test subjects (e.g. patch test).    -   Outstanding care performance on skin and hair. This can be        assessed, for example in test subjects by reference to        subjective skin feel (smoothness, dryness etc.) or haptics and        feel of the treated hair. Mechanical measurement methods, such        as combability of the hair, for example can also be used.    -   Good storage stability. This is then the case if the aqueous        compositions do not exhibit any visible (e.g. cloudiness,        discoloration, phase separation) or measurable (e.g. pH,        viscosity, active substance content) changes over a period of        several weeks.    -   Good applicability and processibility. The compositions can be        dissolved rapidly and without supply of heat on introducing        water.    -   Good clear solubility and transparency. The aqueous surfactant        compositions do not have a tendency to precipitation or        cloudiness.    -   Sufficiently high viscosity, which is understood in the context        of the present invention to mean a value of 1000 mPas or higher        (measured with a Brookfield RV laboratory rheometer at 23° C.,        12 rpm, spindle set RV 02 to 07 (spindle choice depending on        viscosity range)). As is known, “mPas” means millipascal        seconds.    -   Good cleaning performance. The aqueous surfactant compositions        are suitable for removing and emulsifying soiling, especially        fat or oil containing soiling, from solid or textile surfaces.

The Compounds (A)

The compounds (A), which are referred to within the context of thepresent invention as alpha-sulfo fatty acid disalts, are obligatory forthe aqueous surfactant compositions according to the invention. Theyhave the formula (I) specified aboveR¹CH(SO₃M¹)COOM²  (I),

in which the radical R¹ is a linear or branched alkyl or alkenyl radicalhaving 6 to 18 carbon atoms and the radicals M¹ and M²—independently ofone another are selected from the group comprising H, Li, Na, K, Ca/2,Mg/2, ammonium and alkanolamines.

With regard to the radicals M¹ and M², particularly preferredalkanolamines are selected here from the group comprisingmonoethanolamine, diethanolamine, triethanolamine andmonoisopropanolamine.

In a preferred embodiment, the radical R¹ in the formula (I) is asaturated, linear alkyl radical having 10 to 16 carbon atoms, where withregard to the compounds (A) it is the case that the fraction of thecompounds (A) in which the radical R¹ is a decyl and/or a dodecylradical—based on the total amount of the compounds (A)—is 70% by weightor more and in particular 90% by weight or more.

In one embodiment it is the case with regard to compounds (A) that thefraction of the compounds (A) in which the radical R¹ is an alkenylradical—based on the total amount of the compounds (A) in the aqueoussurfactant compositions is 3% by weight or less.

The radicals M¹ and M² in formula (I) are preferably selected from thegroup comprising H (hydrogen) and Na (sodium).

The compounds (A) can be prepared by all methods known appropriately tothe person skilled in the art. A particularly preferred method ofpreparation here is the sulfation of the corresponding carboxylic acids.Here, the corresponding carboxylic acid and in particular thecorresponding fatty acids are reacted with gaseous sulfur trioxide, thesulfur trioxide being used preferably in an amount such that the molarratio of SO₃ to fatty acid is in the range from 1.0:1 to 1.1:1. Thecrude products obtained in this way, which are acidic sulfationproducts, are then partially or completely neutralized, preference beinggiven to complete neutralization with aqueous NaOH. If desired, it isalso possible to undertake purification steps and/or a bleaching (foradjusting the desired pale color of the products).

In a particularly preferred embodiment, the compounds (A) are used intechnical-grade form. This means that the corresponding carboxylicacids, in particular native fatty acid, are sulfated with gaseous sulfurtrioxide, as a result of which, following partial or completeneutralization of the resulting acidic sulfation products, a mixture ofthe compounds (A), (C) and (D) results. By virtue of correspondingadjustments of the reaction parameters (in particular molar ratio ofcarboxylic acid and sulfur trioxide, and also reaction temperature) itis possible to control the ratio of the compounds (A), (C) and (D). Thecompounds (C) and (D) are described below.

In the context of the present invention, preference is given to thosetechnical-grade mixtures of alpha-sulfo fatty acid disalts which havethe following composition:

the content of (A) is in the range from 60 to 100% by weight,

the content of (C) is in the range from 0 to 20% by weight,

the content of (D) is in the range from 0 to 20% by weight,

with the proviso that the sum of the components (A), (C) and (D) in thismixture is 100% by weight.

The Compounds (B)

As detailed above, the aqueous surfactant compositions according to theinvention comprise, besides the compounds (A) and water, one or moresulfo ketones (B) selected from the compounds (F) and (G).

The compounds (F) have the general formula (VI)R⁶CH₂—CO—CHR⁷(SO₃M⁸)  (VI)

in which the radicals R⁶ and R⁷—independently of each other—are a linearor branched alkyl radical having 6 to 18 carbon atoms and the radical M⁸is selected from the group comprising H, Li, Na, K, Ca/2, Mg/2, ammoniumand alkanolamines. In this connection, particularly preferredalkanolamines are monoethanolamine, diethanolamine, triethanolamine andmonoisopropanolamine.

In the context of the present invention, the compounds (F) are referredto as monosulfoketones.

In a preferred embodiment, the radicals R⁶ and R⁷ in the formula(VI)—independently of each other—are a saturated, linear radical having10 to 16 carbon atoms, where, with regard to the compounds (F) it is thecase that the fraction of the compounds (F) in which the radicals R⁶ andR⁷ are a decyl and/or a dodecyl radical—based on the total amount of thecompounds (F)—is 70% by weight or more and preferably 90% by weight ormore. In one embodiment, the radical M⁸ in formula (VI) is selected fromthe group comprising H and Na.

The compounds (G) have the general formula (VII)(SO₃M⁹)R⁸CH—CO—CHR⁹(SO₃M¹⁰)  (VII),

in which the radicals R⁸ and R⁹—independently of each other—are a linearor branched alkyl radical having 6 to 18 carbon atoms and the radicalsM⁹ and M¹⁰—independently of each other—are selected from the groupcomprising H, Li, Na, K, Ca/2, Mg/2, ammonium and alkanolamines. In thisconnection, particularly preferred alkanolamines are monoethanolamine,diethanolamine, triethanolamine and monoisopropanolamine.

In the context of the present invention, the compounds (G) are referredto as disulfoketones.

In a preferred embodiment, the radicals R⁸ and R⁹ in the formula(VII)—independently of each other—are a saturated, linear radical having10 to 16 carbon atoms, where, with regard to the compounds (G) it is thecase that the fraction of the compounds (G) in which the radicals R⁸ andR⁹ are a decyl and/or a dodecyl radical—based on the total amount of thecompounds (G) is 70% by weight or more and preferably 90% by weight ormore. In one embodiment, the radicals M⁹ and M¹⁰ in formula (VII) areselected from the group comprising H and Na.

The preparation of the compounds (F) and (G) is not subject to anyparticular restrictions and they can be prepared by all methods known tothose skilled in the art.

In one embodiment, the compounds (F) and (G) are prepared by sulfonationof the corresponding ketones with gaseous sulfur trioxide, as describedin the German published specification DEA-42,20,580.

In another embodiment, the preparation of the compounds (F) and (G)starts from fatty acids. In this case, the sulfation of liquid fattyacids with gaseous sulfur trioxide is conducted such that, in additionto disalts (A), the compounds (F) and (G) are also formed in this case,which can be accomplished as a result of carrying out the sulfation asfollows: the ratio of fatty acid raw materials, which may also be usedin the form of mixtures of fatty acids of different chain length, tosulfur trioxide is adjusted so that 1.0 to 1.5 mol and especially 1.0 to1.25 mol of SO₃ are used per mole of fatty acid(s). The fatty acids areintroduced into the reactor at a reservoir temperature in the range of70 to 100° C. After the sulfation, the resulting liquid sulfationproduct is maintained and aged at this temperature for 5 to 20 minutesin a temperature-controlled post-reaction coil. Neutralization is theneffected with an aqueous base, preferably sodium hydroxide, generally ina pH range of 5 to 10, especially 5 to 7. Subsequently, an acidicbleaching—the pH here is adjusted to a value of 7 or less—may be carriedout with hydrogen peroxide.

The Compounds (X)

The compounds (X), which are referred to in the context of the presentinvention as sulfates, are obligatory for the aqueous surfactantcompositions according to the invention. The sulfates are selected fromthe group of the alkyl sulfates of the general formula (IIa) and thealkyl ether sulfates of the general formula (IIb)R⁷⁰SO₃M⁷⁰  (IIa)R⁷¹O(CH₂CH₂O)_(n)SO₃M⁷⁰  (IIb)

where the radicals R⁷⁰ and R⁷¹ are independently a linear or branchedalkyl radical having 8 to 20 carbon atoms and the index n is a number inthe range from 1 to 20 and the radical M⁷⁰ is selected from the groupcomprising H, Li, Na, K, Ca/2, Mg/2, ammonium and alkanolamines.

The compounds (X) can be prepared by any relevant methods known to thoseskilled in the art. The alkyl sulfates (IIa) are prepared, for example,by sulfonation of the corresponding alcohols with gaseous sulfurtrioxide, with subsequent neutralization. The alkyl ether sulfates (IIb)are prepared, for example, by SO₃ sulfonation of the correspondingaddition products of ethylene oxide onto the corresponding alcohols,with subsequent neutralization.

In a preferred embodiment, the radical R⁷⁰ in the formula (IIa) is alinear alkyl radical having 12 to 18 carbon atoms.

In a preferred embodiment, the radical R⁷¹ in the formula (IIb) is alinear alkyl radical having 12 to 18 carbon atoms.

In a preferred embodiment, the index n is a number in the range from 1to 4.

Preferably, the radical M⁷⁰ in the formula (IIa) and (IIb) is selectedfrom the group comprising H (hydrogen) and Na (sodium).

In a preferred embodiment, the compounds (X) are selected from the groupcomprising Sodium Lauryl Sulfate, Ammonium Lauryl Sulfate, SodiumLaureth Sulfate and Ammonium Laureth Sulfate (INCI names).

The Compounds (C)

The compounds (C) are obligatory for the aqueous surfactant compositionsaccording to the invention. The compounds (C) have the general formula(III)R⁴COOM⁵  (III)

In the formula (III), the radical R⁴ is a linear or branched alkyl oralkenyl radical having 7 to 19 carbon atoms and the radical M⁵ isselected from the group comprising H, Li, Na, K, Ca/2, Mg/2, ammoniumand alkanolamines. In this connection, particularly preferredalkanolamines are monoethanolamine, diethanolamine, triethanolamine andmonoisopropanolamine.

The Compounds (D)

The compounds (D), which are referred to in the context of the presentinvention as inorganic salts of sulfuric acid (D), are obligatory forthe aqueous surfactant compositions according to the invention. Thecompounds (D) have the general formula (IV)(M⁶)₂SO₄  (IV)

where M⁶ is selected from the group comprising Li, Na, K, Ca/2, Mg/2,ammonium and alkanolamine. Particularly preferred alkanolamines here aremonoethanolamine, diethanolamine, triethanolamine andmonoisopropanolamine.

If desired, the aqueous surfactant compositions according to theinvention can additionally comprise one or more further surfactantswhich, in structural terms, do not belong to the aforementionedcompounds (A), (B), (X), (C) or (D). These surfactants may be anionic,cationic, nonionic or amphoteric surfactants.

Use of the Compositions

A further subject matter of the invention is the use of theaforementioned compositions for cosmetic products, and also detergentsand cleaners.

With regard to cosmetic products, particular preference is given hereespecially to those which are present in the form of hair shampoos,shower gels, soaps, syndets, washing pastes, washing lotions, scrubpreparations, foam baths, oil baths, shower baths, shaving foams,shaving lotions, shaving creams and dental care products (for exampletoothpastes, mouthwashes and the like).

With regard to cleaners, of preference here are in particular productswith a low pH for cleaning hard surfaces, such as bath and toiletcleaners and the like, and also for cleaning and/or fragrance gels foruse in sanitary installations.

The invention claimed is:
 1. An aqueous surfactant compositioncomprising one or more alpha-sulfo fatty acid disalt (A) of generalformula (I)R¹CH(SO₃M¹)COOM²  (I), in which the radical R¹ is a linear or branchedalkyl or alkenyl radical having 6 to 18 carbon atoms and the radicals M¹and M², independently of one another, are selected from the groupconsisting of H, Li, Na, K, Ca/2, Mg/2, ammonium and, alkanolamine, oneor more sulfo ketone (B) selected from compound (F) and the compound(G), where the compound (F) has a general formula (VI)R⁶CH₂—CO—CHR⁷(SO₃M⁸)  (VI), wherein the radicals R⁶ and R⁷,independently of each another, are a linear or branched alkyl radicalhaving 6 to 18 carbon atoms and the radical M⁸ is selected from thegroup consisting of H, Li, Na, K, Ca/2, Mg/2, ammonium, andalkanolamine, and where the compound (G) has a general formula (VII)(SO₃M⁹)R⁸CH—CO—CHR⁹(SO₃M¹⁰)  (VII), wherein the radicals R⁸ and R⁹,independently of each other, are a linear or branched alkyl radicalhaving 6 to 18 carbon atoms and the radicals M⁹ and M¹⁰, independentlyof each other, are selected from the group consisting of H, Li, Na, K,Ca/2, Mg/2, ammonium, and alkanolamine, one or more sulfate (X) whichare selected from an alkyl sulfate of general formula (IIa) and an alkylether sulfate of the general formula (IIb)R⁷⁰SO₃M⁷⁰  (IIa)R⁷¹O(CH₂CH₂O)_(n)SO₃M⁷⁰  (IIb), where the radicals R⁷⁰ and R⁷¹ areindependently a linear or branched alkyl radical having 8 to 20 carbonatoms and the index n is a number in the range from 1 to 20 and theradical M⁷⁰ is selected from the group consisting of H, Li, Na, K, Ca/2,Mg/2, ammonium and alkanolamines, one or more compound (C) of generalformula (III)R⁴COOM⁵  (III), in which the radical R⁴ is a linear or branched alkyl oralkenyl radical having 7 to 19 carbon atoms and the radical M⁵ isselected from the group consisting of H, Li, Na, K, Ca/2, Mg/2,ammonium, and alkanolamine, one or more inorganic salt of sulfuric acid(D) of the general formula (IV)(M⁶)₂SO₄  (IV), where M⁶ is selected from the group consisting of Li,Na, K, Ca/2, Mg/2, ammonium and, alkanolamine, water, where thefollowing proviso applies: if the aqueous surfactant compositionscomprises one or more ester sulfonate (E) of general formula (V)R²CH(SO₃M⁷)COOR³  (V), in which the radical R² is a linear or branchedalkyl or alkenyl radical having 6 to 18 carbon atoms and the radical R³is a linear or branched alkyl or alkenyl radical having 1 to 20 carbonatoms, where the radical R³ can be an alkenyl radical or be branchedonly above 3 carbon atoms, and the radical M⁷ is selected from the groupconsisting of Li, Na, K, Ca/2, Mg/2, ammonium, and alkanolamine, it isthe case that the compound (A), based on the totality of the compound(A) and (E), must be present to an extent of 50% by weight or more. 2.The composition according to claim 1, wherein the radical R¹ in theformula (I) is a saturated, linear alkyl radical having 10 to 16 carbonatoms, where with regard to the compound (A), it is the case that thefraction of the compound (A) in which the radical R¹ is a decyl or adodecyl radical, based on the total amount of the compounds (A), is 90%by weight or more.
 3. The composition according to claim 1, wherein theradicals M¹ and M² are selected from H (hydrogen) and Na (sodium). 4.The composition according to claim 1 for use in cosmetic products,detergents, and cleaners.
 5. The composition according to claim 1 foruse in cosmetic products in the form of hair shampoos, shower gels,soaps, syndets, washing pastes, washing lotions, scrub preparations,foam baths, oil baths, shower baths, shaving foams, shaving lotions,shaving creams, and dental care products.
 6. The composition accordingto claim 1, wherein the alkanolamine is selected from the groupconsisting of monoethanolamine, diethanolamine, triethanolamine, andmonoisopropylamine.
 7. The composition according to claim 1, wherein ifthe ester sulfonate (E) is present, it is the case that compound (A),based on the totality of the compound (A) and (E), must be present to anextent of 90% by weight or more.
 8. A method for cleaning a hard surfaceat a low pH comprising contacting said hard surface with the aqueoussurfactant composition according to claim 1.